Measuring, indicating, and recording instrument



April 12, 1955 sass 2,706,084

MEASURING, INDICATING, AND RECORDING INSTRUMENT Original Filed Sept. 11.1948 8 Sheets-Sheet l oiIIII/IIIIA QATTORNEY.

April 12, 1955 L. GESS 2,706,084 MEASURING, INDICATING, AND RECORDINGINSTRUMENT Original Filed Sept. 11, 1948 8 Sheets-Sheet 2 iii INVENTOR.LOUIS GESS WWW ATTORNEY April 12, 1955 FIG.4

L. GESS MEASURING, INDICATING, AND RECORDING INSTRUMENT Original FiledSept. 11, 1948 8 Sheets-Sheet 3 PM: I

MI Ii IIIIIHHUIIlllllllllllllliiliiiiiiiii""' m II" I II WWW JNVENTOR.LOUIS GESS ATTORNEY April 12, 1955 GESS 2,706,084

MEASURING, INDICATING, AND RECORDING INSTRUMENT Original Filed Sept. 11,1948 8 Sheets-Sheet 4 JNVENTOR. T H LOUIS GESS ATTORNEY L. GESS April12, 1955 MEASURING, INDICATING, AND RECORDING INSTRUMENT 8 Sheets-Sheet5 Original Filed Sept 11, 1948 INVENTOR. LOUIS GESS ATTORNEY.

April 12, 1955 555 2,706,084

MEASURING, INDICATING, AND RECORDING INSTRUMENT Original Filed Sept. 11.1948 8 Sheets-Sheet 6 INVENTOR. LOUIS GESS ATTORNEY L. GESS A ril 12,1955 MEASURING, INDICATING, AND RECORDING INSTRUMENT 8 Sheets-Sheet 7Original Filed Sept. 11, 1948 INVENTOR. LOUIS GESS ATTORN EY.

L. GESS April 12, 1955 MEASURING, INDICATING, AND RECORDING INSTRUMENTOriginal Filed Sept. 11, 1948 8 Sheets-Sheet 8 FIG. l2

SOT

FIG.

AIR SUPPLY L INVENTOR. LOUIS GESS ATTORNEY.

MEASURING, INDICATING, AND RECORDING INSTRUMENT Louis Gess, Jenkintown,Pa., assignor to Minneapolis- Honeywell Regulator Company, Minneapolis,Minn., a corporation of Delaware September 11, 1948, Serial No. No.2,666,585, dated January 19, this application June 1, 1953, Se-

Original application 48,856, now Patent 1954. Divided and rial No.358,697

6 Claims. (Cl. 236-51) This application is a division of co-pendingapplication Serial Number 48,856 in the name of Louis Gess, filedSeptember 11, 1948, now U. S. Patent 2,666,585, patented January 19,1954.

In many modern industrial and in some cases impossible for the operatoror person having charge of the process to be close to it. This is forthe reason that such processes are so hot, dirty, noisy or dangerousthat it is inadvisable for a human being to be at their immediatevicinity.

It is a theoretical ideal that processes be made completely automatic.Obviously this theoretical ideal cannot be realized completely in actualpractice because in the beginning the process must be started up andmust, eventually, be shut down. Therefore it is necessary that means beprovided to control such processes from a remote point, hereinafterreferred to as the control location. In order to exercise the control ofsuch a process, there must be (1) a final control element, such as avalve, controlling one process variable; (2) a measuring elementresponsive to. the variable under control; and (3) a con troller,whereby the measuring element actuates the final control element. Such acontroller usually involves a separate source of power and a relaywhereby the measuring element, which is sensitive and therefore haslittle driving power, actuates the final control element, which may bevery large and therefore require considerable power to drive it.

Moreover, the apparatus in which industrial processes of the characterreferred to are carried out is often enormous in size, constitutingcomplete industrial plants, in which the several process variablesinteract or are correlated so that the variations of one affect one ormore other variables.

It is known to assemble means for controlling the separate final controlelements at one control location in a centralized control room which maybe equipped with instruments for indicating and recording the control ofmany variable functions such flow or liquid level. A panel board onwhich the various control means are arranged is located at the controlroom.

It is an object of this invention to provide at such a control locationan indicator or recorder to inform the operator that the controloperations which he has initiated from the control location have beentransmitted to the various final control elements located throughout theplant and that the consequent operations of these final control elementshave-actually aflected the process under control in the desired manner.

A further object of this invention is to provide airoperated means forcontrolling the final control elements and for reporting back theoperations of the final control elements to the control location. Theadvantages of airoperation for these purposes are well known. Foremostamong these advantages is the removal of the explosion hazards whereexplosive gases or fluids are present. Additional advantages are theinherent stability, accuracy and flexibility of air operation.

Yet another object of this invention is to provide a control systemhaving manually operable elements-at a control location from which acontroller located adjacent the final control apparatus can becontrolled by hand so that the operations of the controller vary thefinal conprocesses it is undesirable as temperature, PI'ESSHTC,

trol element as quickly as possible with a minimum of lag or delay.

A still further object of this invention is to provide a control systemhaving indicator or recorder at the control location and under the toindicate the movements of the controller and having a measuringinstrument located adjacent the process vari le under control andarranged to be sensitive to changes in this process variable.

t The various features of novelty which characterize this inventionpreferred embodiment of the invention.

e drawings: Fig. l is a front elevetion of the transmitter and theadjacent indicator.

Fig. 2 is a diagrammatic Fig. 4 is a rear elevation of the transmitterand indicator with the rear cover removed as viewed from the line 44 ofFig. 3.

Fig. 5 is a front elevation of the controller with the front coverremoved showing parts in vertical cross sectron.

Fig. 6 is a diagrammatic or schematic showing of a complete pneumatictransmitting, controlling and indi cating system according to thisinvention.

Figs. '7 through 9 are diagrammatic or schematic showings ofmodifications.

Fig. 10 is a diagrammatic additional modification.

Fig. 11 is a diagrammatic tabulation showing the arrangement of theports of one valve, of Fig. 10.

Fig. 12 is a diagrammatic or schematic showing of an additionalmodification.

Fig. 13 is a diagrammatic tabulation showing the arrangement of theports of one valve, of Fig. 12.

FIGS. 1 AND 2 Fig. 1 shows the front or face of the transmitter which islocated at any convenient control station, such as the panel board.

or schematic showing of an 12 bearing a flapper-operating pin 13. Pin 13is movable into and out of engagement with a flapper'14 which ispivotally movable about a stationary pivot 15. Flapper 14 is stressed bya spring towards engagement with a nozzle 16. Nozzle 16 forms thecontrol of a pilot valve of a Well known commercial type which includesan air inlet pipe 17 which admits air to a forked channel. One fork orbranehof the channel leads through a filter 18 and an adjustablerestriction 1? to a pipe 20 ending at nozzle 16 and to a branch pipe 21leading to casing 22 which contains outer bellows 23. Secured to bellows23 is one end of a hollow exhaust pipe 24 which is also secured to theinner bellows 25 which seals the exhaust pipe to the pilot valve orrelay casing 26. The lower end of exhaust pipe 24 is scaled by a secondflapper 27 when the exhaust pipe 24 engages the flapper 27. Flapper 27also controls the main flow of air through the nozzle 28. Exhaust pipe29 leads to the receiver or other device controlled by the pilot valveor relay. Feedback pipe 30 leads from the oil-take side of theflapper-chamber and communicates with bellows casing 31 containing abellows 32 stressed by a spring 33 and having its motion limited in onedirection by a cylindrical control of the controller so as stop 34.Motion of bellows 32 is transmitted to a differential, one input ofwhich is provided by the manually caused movement of knob 1 and theother input of which is formed of the resetting movement of bellows 32.Bellows 32 moves a link 35 at the end of which is formed a pin 36slidable in a slot 37. A bell crank lever 38 is pivotally mounted on astationary pivot 39 and contains in it an opening 46 through which theshaft 11 passes.

FIGS. 3 AND 4 Figs. 3 and 4 show this manually operated transmitter ingreater detail. The knob or handle 1 is rotatably mounted in the panelso that its front face is substantially flush with the front face of thepanel. The shaft 5 is stressed by a spring ll which tends to take up anyback lash which there may be in the gearing 6. The bell crank lever 7 isbiased for counter-clockwise rotation by a spring 42 one end 43 of whichengages the bell crank lever 7 and which is fastened to the instrumentcasing at its opposite end means of link 9 and lever 10, turns shaft lland pin 13 carried thereby. Spring 45 has one end 46 fast to theinstrument casing and stresses at its other end 47 against the bellcrank lever 38, tending to hold the bell crank lever 38 against the pin36 which is located in the slot 37 forming a part of the lever 38. Theair inlet 17 communicates with the pipe 2% which leads to the nozzle 16while the air outlet pipe 29 communicates with the pipe 30 which leadsto the casing 31 which contains the reset bellows.

Operation of Figs. 3 and 4 The operation of the manually operatedpneumatic transmitter will be readily understood by referring to Fig. 2.When the manually operated transmitter is turned, it operates thereceiver which is connected to the air outlet pipe 29 so as to adjustthe set point or control point of a controller located at a remoteplace. Turning knob 1 in one direction or the other operates the flapperpin 13 through the mechanical linkage formed by shaft 5, gearing 6, bellcrank lever 7, link 9, lever it), shaft 11, and lever 12. Movement ofpin 13 in engagement with flapper 14 turns the flapper 14 under thestress of its actuating spring about the flapper pivot 15. The movementof flapper 1-:- relative to nozzle 16 varies the air pressure applied tobellows 23 and causes consequent movement of exhaust pipe 24 so thateither air is exhausted from the pilot valve or the flapper27 is movedaway from nozzle 28 to admit additional air to the pilot valve chamber.When sufiicient air is exhausted from or admitted to the pilot valve,the bellows contracts or expands and the flapper 27 closes ed theexhaust pipe 24 and the inlet nozzle 28. The air controlled by the pilotvalve flows through the outlet pipe 29 to the receiver connected to theopposite end of pipe 29. The con trolled air within the pilot valve isalso fed through pipe 30 to the bellows casing 31 wherein it causesconseq'uent movement of bellows 32. The movement of bellows 32 (due toany difference existing between the air pressure in the bellows casing31 and the stress of spring 33) is transmitted by the link or bellowsrod 35 to the lever 38. Rotation of lever 33 in one direction or theother rotates flapper pin 13 in the opposite direction to which it. hasbeen set by knob 1 and thus resets 'the flapper 14 so as to control theair pressure within the bellows casing 22 at the new value desired.

FIG. 5

Fig. 5 shows the details of a controller which is located adjacent thevalve or other final control element. This controller may be of the typeshown in U. S. Patent 2,125,081, granted July 26, 1938. This controllercontains a measuring element, which is shown as being a thermometerformed by a spiral or Bourdon tubing 43 actuated by liquid or vaporpressure from a suitable bulb 49 located at the point, whose temperatureit is desired to measure. However, instead of a measuring element fortemperature, a measuring element for pressure, flow, or liquid level maybe employed. The movement oi the measuring element 4-8 forms one inputof a differential, generally indicated at The other input ofdilferential 59 is provided by an air-operated receiver, generallyindicated at 51, and connected to the manually operated transmitter by apipe 29. Receiver 51 is formed by a bellows casing 52 containing abellows 53 which is matched to or interchangeable with the bellows 32 of44. Bell crank lever 7, by

4 the manually operated transmitter. Bellows 53 is stressed by a spring54 and has its movement in the direction in which it is operated by theair within the bellows casing 51 limited by a cylindrical stop 55.Bellows 53 engages one end of a bellows rod or link 56 whose oppositeend has pivotal engagement with a lever system, generally indicated at57. The output of lever system 57 is transmitted by link 58 which formsone input of the differential, generally indicated at 50.

' obtained, may be limited by the The transmitter operated transmitterexcept that the link has pivotal engagement ports the three-armed lever74 tion opposite to its original movement in order to The position ofmeasuring element 48 is also fed to a second transmitter, generallyindicated at 59, by means of a link 61 which controls the setting of thepin 61 operating the flapper 62 with relation to the nozzle 63. 59 hasthe same elements as the manually link 6%, which is the equivalent ofthe manually operated link 9 of the manually operated transmitter, isoperated by measuring instrument 48 instead of manually. The nozzle 63is connected by a pipe 64 to a pilot valve, generally indicated at 65,and having an air inlet pipe 66 and an air outlet pipe 67. This airoutlet pipe 67 is connected to and actuates the indicator 2 at thecontrol station to indicate at the control station the value of thevariable being measured at that instant by the measuring element of thecontroller at the remote location. Control of the final control element,such as a valve operated by an air-driven diaphragm motor or the like,is exercised by a pilot valve or relay, generally indicated at 68,having an air inlet pipe 69 and an air oil-take 70 to the valve or otherfinal control element. This controller is a well known commercial typeand has an adjustable throttling range and an automatic reset. The pilotvalve 68 is controlled by means of. a nozzle 71 which is responsive tothe flapper 72 controlled in turn by a flapper-actuating pin 73 mountedon a three-armed lever 74 pivoted at 76, which i is actuated from thedifferential 59 by means of a control link 75.

Movements of the measuring element 48 are transmitted by a spring arm 77to the arm 78 of a three-armed lever mounted on a stationary pivot 79.Arm fill of this three-armed lever is connected to one end of link 69.The third arm 81 of this lever has pivotally connected to its free end adifferential link 82 which is pivotally secured at its opposite end toone end of a floating lever 83. The opposite end 84 of lever 33 iscarried by one arm 85 of a second three-armed lever pivotally mounted ona stationary pivot 86. A second arm 37 of the three-armed lever pivotedat 86 has a pivotal connection with the free end of link 53, while thethird arm 8&A of the lever pivoted at 86 forms an indicator or pointerdenoting the location of the set point of a controller. The control withthe floating lever 83 at point 89A, intermediate the ends of thefloating lever 83. Thus the output of the differential 59 is connectedby means of control link 75 with one arm of the three-armed lever 74that is pivoted at 76. This lever has a pin 73 on it wh ch serves tomove flapper 72. against a suitable biasing force away from or to permitthe flapper to move toward nozzle 71 to throttle the flow of air throughthis nozzle. The nozzle 71, along with a chamber formed in the pilotvalve 63, is supplied with air from pipe 69. A restriction is formed inthe supply pipe to the nozzle 71 and the chamber so that air is suppliedthereto at a slower rate.

As the pressure in the chamber is varied, a follow-up movement is givento the flapper 72 by means of the action of a rod 88 and a projection 89thereon upon a first lever N) that is pivoted at 91, a pin 92 and asecond lever 93 that is pivoted at 93a, which second lever supby meansof pivot 76. This pin 92 is attached to a supporting arm Q4 and may bemoved upwardly and downwardly between levers 9%) and 93 to change thethrottling range of the instrument. As the lever 93 is moved, theflapper is shifted in a (greering the instrument back to equilibrium.This second or follow-up movement is followed by a third compensating orreset movement. As pressure of the liquid in the chambers betweenbellows 95' and 96 and bellows 9'7 and S 3 is equalized through theconnection 99, the speed at which this reset motion can take place isdependent upon the adjustment of the restriction 108.

The total amount of follow-up movement that can be amount of movementthat can be imparted to the lever 93. To this end the lever 93 is formedwith a pair of fingers 101 which extend on either side of a shaft 102.

Operation of Fig. 5

In the operation of the instrument, if, for example, the temperaturebeing measured has been increased, the pen 88A will be moved in acounter-clockwise direction outwardly across its chart. This samemovement will cause the left-hand end of differential lever 83 to belowered so that control link 75 will move lever 74 in a clockwisedirection. Such a movement will move the pin 73 to the left so that theflapper 72 will be moved away from the nozzle 71, permitting more air toescape from this nozzle with a consequent decrease in pressure in thechamber. of the pilot valve 68. The escape of air from the chamber ofthe pilot valve 68 will also cause a reduction of pressure in thechamber. surrounding the bellows 96 thereby permitting the rod 88 with.its projection 89 to move to the right. The levers 90 and 93 and thepin 92 will therefore cause a movement of the pivot point 76 and lever74 to the right so that flapper 72 will be given a follow-up movementtoward the nozzle 71. If the temperature being measured deviates aconsiderable amount from the control point of the. instrument, the lever93 will be forced to move in a clockwise direction until the lower oneof the members 101 engages with rod 102 to stop further movement of thislever. Thereafter, the control instrument operation in that directionwill be as an on-oif instrument, since no further follow-up can beobtained.

In like manner, a decrease in the temperature being measured will causea reverse operationto that above described so that an increase inpressure is obtained throughout the system with the lever 93. moving ina counter-clockwise direction to an extent limited by engagement betweenthe upper member 101 and the shaft 102. It will therefore be seen thatan air pressure corresponding to the temperature being measured will beset up in the chamber of the pilot valve 68 and this pressure will bevaried with the changes in temperature within reasonable limits oneither side of the control point. When the temperature changes beyondthese limits, however, further follow-up movement cannot be obtained dueto engagement of one of the members 101 with the shaft 102. Thereafter,the pressure in the chamber in the pilot relay 68 will go immediately toone of its limits. The amount of deviation from the control point, whichis permitted the temperature prior to the time that the members 101engage the shaft 102 can be varied.

FIG. 6

Fig. 6 shows in a diagrammatic or schematic form, a completetransmission system. The transmitter and its associated indicator (shownin detail in Figs. 3 and 4) are located at the left within the dottedand dashed lines Z, while the (shown in detail in Fig. 5) is indicatedat the right within the dotted and dashed lines Fig. 6 shows that theknob 1 controls the operation of flapper 14 cooperating with nozzle 16.Inlet air from pipe 17 branches and passes through restriction 19 andpipe 20 to nozzle 16 and also passes to the inlet nozzle 28 of the pilotvalve or relay 26. Flapper 27 controls the admission of air throughinlet nozzle 28 and the escape of air through exhaust pipe 24. Exhaustpipe 24 is operated by bellows 23 within casing 22 in response to theair pressure maintained at nozzle 16 and transmitted through pipes 20and 21.

Outlet pipe 29 conducts air from the pilot valve or relay 26 to thereceiver, generally indicated at 51, and having bellows 53 within casing52. The controlled air from pilot valve 26 is fed back through pipe 30to bellows casing 31 where it actuates bellows 32 to reposition flapper14 by means of the differential shown in detail in Fig. 2.

Referring now to the controller within the dotted lines Y, it will beseen that the measuring element 48 feeds of the differential, generallyindicated at 50. The opposite end of the ditferential is fed from thereceiver 51 by the linkage shown in detail on the righthand of Fig. 5.The motions of measuring element 48 are fed directly to flapper62 whichcooperates with nozzle 63 forming part of the transmitter, generallyindicated at 59. This transmitter comprises a pilot'valve 65 to whichair is fed from the pipe 66. This inlet air passes through restriction105 to pipe '64 which terminates in nozzle 63. Pipe 64.also contains abranch 106 comreality of final control elements municating with abellows casing 107 in which are housed.

bellows 108. Pilot valve has a flapper 109 controlling an exhaust nozzle111 forming the end of inlet pipe 66. Off-take pipe 67 leads back to theindicator 2 located at the control station adjacent the handle 1. Pipe67 also communicates with pipe 112 which leads back to bellows casing113 containing bellows 114 which feed into a dif ferential so as to giverepositioning movement to flapper 62. The movements of measuringinstrument 48 and of the receiver 51, which moves the control point orset point of the controller, control the actuation of the final controlelement, such as valve 115, by means of a pilot relay 68 to which air isled through an inlet pipe 69 and from which air escapes through a pipe70. Pipe also communicates with the throttling and reset mechanismexplained in detail in connection with Fig. 5. This mechanism serves toreset flapper 72 by means of pin 89. Inlet air from pipe 69 passesthrough restriction 116 and through pipe 117 to nozzle 71. Pipe 117contains a branch 118 communicating with a bellows casing 119 containingbellows 120. The full flow of air from pipe 69 passes through inletnozzle 121, controlled by a flapper 122, which also controls the exhaustpipe 123 which is moved by bellows 120.

Operation of Fig. 6

When it is desired to adjust the setting of the controller actuating thefinal control element 115, knob 1 is turned so" as to adjust flapper 14relative to nozzle 16. This varies the air pressure in bellows casing 22and causes exhaust pipe 24 to either exhaust air from pilot relay 26 orto move flapper 27 to admit additional air to pilot relay 26 throughnozzle 28. This change in air pressure in pilot relay 26 is transmittedthrough pipes 29 and 30 to bellows casing 31 where it causes bellows 32to reposition flapper 14 to a value corresponding to the pressure thusmanually established by turning handle 1. The output pressure throughpipe 29 is also transmitted to receiver 51 where it actuates bellows 53and through a differential thereby affects a throttling as has alreadybeen described.

It will thus be seen that this transmission system atfords means wherebya final control element 115 may be sponsive to the measuring element 48,have the same elements to which the same reference. characters have beenapplied as m Fig. 6, and operates in the FIG. 8

Fig. 8 shows a further modification in which a pin 121, 122 and 123 canbe pipe actuated by bellows 108 and inlet,

assent 7 tsidibir "sid t tid sii a fi wi tsd e m pan li lnea sd e h QFZEQ I o w ts tra location from which'the controllerofap entne ind trialprocessingplant is exercised. There isalso provided at thiscont'rolstation, a; multi-p'en' recorder whichrecords the movements of each ofthe final control elements.

The manually operable handles 124:, 125,- and' 126 are the operating"mechanismsof pneumatic transmitters whiplr operate'pneumaticreceivers1'27, 128, and 121s spectively. These'receivers 127, 123, and 129', feedinto differentials 130,- 131, and 132, IespectivelL- a's' well asoperating setp oint idicatots 133, ifafhand 135, re spe-c-- tively.Adjac cnt the final-control elements 121, 122-, and 123 an;controllershaving measuring elements 136, 137, and 138, respectively.These measuring elements" also feed; into the differentials 13%; 13.1,and 132,- and' like wise operate indicators 139, 14%, and 141- andi alsooperatepn'eumatic transmitters 14-2, 143, and 144', respectively. Thesepneumatic transmitters 142, 1'43, and 144 are connected to pneumaticreceivers 145, 1 46; and 147, respectively. These receivers actuate penarms. 1'48,- 14,= and 150,-respect'iv'ely. The differentials 130, 131,and 132 control flappers cooperating with nozzles 151, 152,- and' 153';respectively. These nozzles form parts of pilot valves 154, 155, and 156whichhave, respectively, ol'ftake pipes 157, 158, and 159 leading to themotor [or the final control elements 121, 122, and 123, respectiv Theoil-takepipes 157, 158, and 159 also lead to throttling and resetmechanisms 160, 161, and 162, respectively, ghosg action has beenexplained in the description at 'he'rnodificatio'n of Pig. 8 thus showshow a number of final control elements can be actuated from a singlecontrol station under the control of a single operator and thevariations sensed by measuring elements adjacent thesefinal controlelements can be recorded on a single multi-chart at the controllocation.

FIG. 9 Fig. 9 shows a pneumatic transmission system which provides meansfor setting the index of a controller located at a remote point and foralso providing a record of the control point of that instrument at thecontrol station. At the control station; there is located within thelines X an instrument having the outward appearance of a controllerequipped with a pen 163', an index 164 and a setting knob 165 for theindex. The manually-operable setting knob 165 feeds into a differentialwhich controls the flapper 166 of a pneumatic transmitter. This;pneumatic transmitter includes an air supply pipe 167 which feeds airthrough a restriction 1 68 and a pipe 169 to a nozzle 17.6) cooperatingwith the flapper 166. The pipe 169' has a branch 171 leading to abellows housing 17.2 containing a bellows 173. Inlet pipe'167 terminatesin inlet nozzle174 cooperating with a flapper 175 which also cooperateswith an exhaust pipe 176 movable in response to the movements of thebellows 173'. Flapper 1'75 is located in a pilotvalve' casing 177 havingan offtake pipe 173 fron'rwhich branches a pipe 172 leading to. bellowscasing 189 in which are housed bellows 181 which feed into a'differential so as to operate or reposition the fiapper 166. Theoutletpipe 17 8 ieadsto an airoperatedreceiver 51 formingpart of acontroller located within the dqttid and dashed lines Y and.corresponding to the controllers shown in Figs. 6 and 7. When theoperator turns the manually operable handle 165, he does not directly.change the set point of the instrument at the control station butinstead sets in motion pneumatic transmission apparatus which sends apressure to the remotely installed controller within the lines Y wherethe index is positioned automatically. In orderto provide rapid andaccurate setting of the index on the controller, use is made ofpneumatic tra'nsmitterunits. This eliminates the inching operation whichis necessary when a. pressure regulator is employed for this purpose.Furtherm0re,-the

use of such a transmission system results in maintaining position of theindex without deviation or drift. Moreover, the consumption of air isreduced to an absolute minimum.

FIG. 10

This modification is a controller by means of which a final controlelement is controlled either manually or automaticallyand in which thereis provided means for adfrom a control location the set point of aprimary 1. 1 3 controller or or a secondary controller, which are thestains in? automatically (Controlling the final cannot ele-' ment.

Filtered air suppl y 200 is controlled by a first manually operableair-pressure regulator20'1 which is mounted on" a panel similar to thepanel shown in Fig 1. This panel-is" at a controllocation which mayconveniently be the control room or other place from which anentire industrial process plant is controlled. The various final control elementsare located a't'various lo'cationsthroughout-the plant remote from thecontrol location. From the pressure regulator 2(31 a pipe 202- leads to'a' switching valve 203; The switching-valve 263 is manually operable andmay be of various structural forms; The form ill-ustrateddiagrammatically in Figs. 10 and 1 1' is a cylindrical ill - casinghaving seven ports'through it control location.

air from relay valve 236 branches;

hich are indicatedin the drawings by the reference characters A, 8, 0,D, E; F,-. and G. plug having channels through it which connect the various ports A-G to one another in sequence of five steps- 1 shown in Fig.ll.

The pipe 292 connects with the port A. The; port E connects. with theair-operatedmotor 294 for the final control element 205 which is locatedat sornepoint in the plant or process controllingapparatus remote'fr'omthe 1 Port E is also directly connected to an air-pressure-operatedindicator 296 located at the control panel so as to indicate thepressure appliedto motor 204. The same source of filtered air supply 2%or second source of air supply 207 communicates with a; second manuallyoperable air-pressure regulator" 268 from which an outlet pipe 2tl9leads to the Valve p'ort C. Valve'port D is connected by means ofpipe210 with a pair of relatively movable parts constituting anair-operated receiver 211. Receiver 211 for-ms part of a sec-' ondarycontroller, generally indicated at 212, which is of the type disclosedin detail in Fig. 5 The parts of controller 212 are located within acontroller casing 213. A nozzle 214 is controlled by a flapper valve215. A: measuring element 216 forms one input to a difi'erential linkage217 including a movable pivot. A pilot valve has a motor 222 operated inresponse to the flow of air through nozzle 214. Filtered air supply 21leads to nozzle 22% and to restriction 221 in the pipe leading to nozzle214. Motor 222 operates exhaust pipe 223 by means of a mechanicallinkage. Pilot valve 218 has a' flapper 224 controlling nozzle 22% andexhaust valve 223'. The outlet pipe 225 from pilot relay 218 branches.Pipe 226 leads to a reset device 227 which has ameehanical linkage 228to. arm 222 of differential 217... Receiver 211 has a mechanical linkage230 with arm 231 of differential 217. The opposite end of arm 231 isconnected to measuring instruntent216. The output of differential 217 isthe flapper pin 232 which actuates flapper 215.

The otherbranch of pipe 225 is pipe233 which conmeets at its oppositeend with port G. of switch-ingvalve 2B3; Pipe 234 parallels this endportion of pipe 233 and connects at'its end toindicator 235.

Filtered air supply 219 also supplies air to an air-operi atedtransmitter made up of a pilot valve 235 having an inlet nozzle 23! andan exhaust valve 238 controlled by a flapper 23?. Filtered air supply219 is also connected to restrictionZll from which one pipe leads.through an air-operated motor .241 and a branch. pipe24 2 leads to'apozzle 243 controlled by a flapper 24. The output- One portion; passesthrough a' pipe 245 to an air-operated motor. 246 which constitutes arepositioning device having a mechanical con"- nection247 to oneeud ot'a differentialarm 248the opposite end of which is connected by means ofamechanical linkage, 249 to measuring instrument 216 through difierential 217, if desired. The output of differential 248 is thefiapperactuating pin 250.

The" other portion of the output air from relay 236 passes through pipe251 to an air-operated receiven252 forming part of a recorder generallyindicated at 253. A pivotally mounted pointer or per: arm 25% ispivotedwith-i in a recorder casing so as to pass over a chart 255 andrecord a marking on the chart. V

A second controller similar to that shown in, Fig. .6 and to thatgenerally indicated at 212 is generally indicated at 256. Thiscontroller has the filtered air supply. 257 which brdnches. One portionof this ainis suppliedto a nozzle. 25% of a pilot valve or relay 2S9having an exhaust valve 26il,which,- together with a nozzle 25,8;jscontrolled by flapper 265.. Another portion of the air from inlet 257passes through restriction 262 to noz- The movable element of the valvezle 263 controlled by flapper 264 and to motor 265 which operates relayvalve 259 by means of the exhaust port 260. One portion of the outletair from relay 259 passes through pipe 266 to port B of switch valve 203while the other portion of the outlet air from pilot valve 259 passesthrough pipe 267 to reset device 268.

From port F of switch valve 203, pipe 269 passes through an air-operatedreceiver 270 which is connected to one end of a lever 272 which formspart of a diflerential generally indicated at 271. A measuringinstrument 273 is connected to the opposite end of lever 272.

The output 274 of lever 272 connects to one end of a second differentiallever 275 whose opposite end is driven by a mechanical connection 276from reset device 268. The output of differential 271 is formed byflapper pin 277. A mechanical connection 278 leads from measuringinstrument 273, to differential 271, if desired, to one end of adifferential lever 279 whose output is formed by flapper pin 230. Pilotvalve 281 has a nozzle 282, connected to filtered air supply 257, anexhaust valve 203, and a flapper 284-.

Air from supply 257 also passes through restriction 285 to anair-operated motor controlled by flapper 209.

The outlet air from pilot relay 231 branches. One portion passes upthrough pipe 290 to an air-operated motor 291, constituting arepositioning device, having a mechanical connection 292 to the oppositeend of differential lever 279. The other portion of the outlet air FIG.11

This figure is a diagrammatic or schematic showing of the connectionsbetween the various ports of the switching valve 203 in each of thevarious, successive steps by which this controller performs variousoperations. When it is desired to start up the process under the controlof the final control element 205, the switching valve is operated intothe position in which it is shown in Fig. 11, step 1, in which the valveports A and E are connected. Air thus passes from the inlet 200 throughthe first manually-operable air-pressure regulator 201, pipe 202, theswitching valve ports A and E to the motor 204, which operates the finalcontrol element 205, and also to the first air-pressure-operatedindicator 206, which indicates the instantaneous value to the motor 204and consequently the position of the final control element the set pointof the secondary controller 212 so that it can assume control of thefinal control element 205 and maintain the final control element at theposition to which it has been set by the manually operable pressureregulator 201. In order to do this, the switching valve 203 is turnedinto the position in which it is shown in Fig. 11, step 2. In thisposition, ports A and E of switching valve 203 remain connected so thatthe manually operable pressure regulator 201 can adjust thevalve-operating motor 204. At the same time, ports C and D of switchingvalve 203 are connected. Air enters from supply 207 and passes throughsecond manually operable air-pressure regulator 20%, pipe 209, valveports C and D, pipe 210, to receiver 211. Second regulator 208 can bemanually adjusted so that movement of receiver 211 moves linkage 230,and diiferential 217 so as to adjust the position of flapper 215relative to nozzle 214 and thereby control the flow of air throughsecond pilot or relay valve 218. The control flow of outlet air fromsecond pilot or relay 218 passes through pipe 233 to secondair-pressure-operated indicator 235 which is located at the controllocation adjacent the first indicator 206. This permits the air pressureapplied to the motor 204 to be compared readily with the air presusreapplied to the controller 212. When these two pressures are equal orapproximately equal, step 3 can be taken. This step consists in takingthe control of the final control element 205 away from the firstmanually operable airpressure regulator 201 and connecting the motor 204under the automatic control of the secondary controller 212. Fig. 11,step 3, shows that this is done by shutting off the connection betweenports A and E and making 10 a connection between ports G and E ofswitching valve 2- The motor 204 is thus connected under the control ofthe measuring instrument 216 of the secondary controller 212. If it isdesired to adjust the set point of the secondary controller 212automatically instead of manually, by means of the second manuallyoperable air-pressure regulator 200, the switching valve 203 is nextturned into the position in which it is shown in Fig.

Then step 5 is taken by turning the switching valve 203 into the In thisposition, motor 204 13 connected through valve and D, and pipe 210 tothe first air-operated receiver 211. These connections allow the primarycontroller 256 to adjust the set point of the secondary controller 212which in turn controls the position of the final control element 204.

FIG. 12

This figure discloses an air-operated controller for manually orautomatically operating from a control location a motor-driven finalcontrol element positioned at a place which air at a suitable pressureis supplied to a first manually operable air pressure regulator 301 atthe control location. From regulator 301, a pipe 302 leads to aswitching valve 303. Switching valve 303 is shown in Figs. 12 and 13diagrammatically. various physical embodiments but the preferredembodiment consists of a tubular or cylindrical casing having eightports or openings through it. These ports or openrugs are designated bythe reference characters H, J, K,

M, O, P. rotatably mounted a plug having openings through it connectingthe various ports. From port L, a pipe 304 leads to motor 305, such asan air-operated diaphragm motor, for final control element 306. A branchpipe 307 leads from pipe 304 to a Bourdon tube 303 or similarpressure-responsive device which operates a first air-pressure-operatedindicais also connected to the filtered air source 300. A pipe theoutput side of the second regulator 31!.

of the switching valve 303. A pipe 313 convalve 303 to a pair ofrelatively movable parts, such as an air-tight casing and a flexiblebellows, constituting a first air-operated receiver 314. A nozzle 315 iscontrolled by a flapper A differential linkage 317 including a movablepivot is driven by a mechanical linkage 318 from said first so as toadjust the flapper valve 316. A pilot valve 319 is operated by anair-operated motor 320 through a pipe 321 communicating with a pipe 322which terminates at the nozzle 315. An outlet pipe 323 from switchingvalve 303. branch pipe 324 connects pipe 323 with a secondairpressure-operated indicator comprising a Bourdon or like pressureoperated element 325 which moves a second indicator 326 across scale 310out of the path of motion of pointer 309.

A controller, generally indicated by 327, is located at the remotelocation adjacent the final control element 306 Within the controllerand has a measuring element 328. casing 329 is a second pair ofrelatively movable elements 336' suchas an a irtightcasing and acooperatingflexible air pressure which passes through gauge 3361 A pipe337 contains a restriction 333 and branches into pipe 339 whichterminates in nozzle 331 and pipe 346 which coinmunicates with anair-operated motor 341 comprised oi an air-tight casing; and acooperating flexible bellows. A pipe 342 leads off from the second pilotvalve 334. Air is supplied to the reset device 330 from pipe 342 througha pipe 343.

7 From port N of switching valve 393, a pipe 344 leads to a third pairof relatively movable elements constituting a second air-operatedreceiver 345. A mechanical linle age 346 connects the receiver 345 withone end of the differential 317 so that movements of the second receiver345 are transmitted through differential 317 to the first flapper valve316. At the control location there is provided a recorder, generallyindicated at 347, and having a third pair of relatively movable elementsconstituting a third air-operated receiver 348 communicating with thesecond pilot or relay valve 334 through pipes 342 and 349. A mechanicallinkage 350 drives a pen arm 351 from the third receiver 343 so that thepen arm marks a chart 352 in the recorder 347.

There is also provided a primary controller, generally indicated at 353,and having a second measuring element 354 and a manually operable indexsetting knob 355 connected to a diflerential linkage 356 which drives athird flapper valve 357 controlling the fiow of air through a thirdnozzle 353 which controls an air-power motor 359 forming the operatingmechanism for a third pilot valve 36% which constitutes a secondtransmitter. A source of filtered air 361 supplies air at full pressureto the nozzle 362 of the third pilot valve 36% and also supplies airthrough a restriction 363 at a reduced pressure to nozzle 35,3 and motor359. A pipe 364 connects the output side of the third pilot valve 360with port K of switching valve 393. 7

Operation of Fig. 12

Fig. 13' shows diagrammatically the connections betvveen the variousports of the switching valve 303 as this valve is turned in a sequenceof five steps to connect the various parts of the control system. Whenit is desired to start up the process under control of the final controlelement 386, switching valve 303 is turned into the position shown inFig. 13, step 1. Port H is connected to port L so that air flows fromsource 309 through first manually operable pressure regulator 3G1, pipe302, ports H and L, and pipe 334 to motor 395. Branch pipe 307 also canducts this air to Bourdon tube or spiral 3% so that the firstair-pressure-operated indicator indicates by means oi pointer 3&9 andscale 31% the pressure which is applied to motor 3595 and consequentlyto the final control element 3436; At the same time the control point ofthe controller 327 is observed onthe recorder 347 just above theindicator 363 -316. In order to prepare the controller to automaticallycontrol thefinal control element 306 from the measuring element 323, theset point or air pressure sent out from pilot or relay valve 319 must beadjusted so that it is substantially equal to that currently applied tomotor 395. if the pressure to be applied to the motor 395 should bediiierent from that being applied, the process controlled by the finalcontrol element 396 would be disturbed. Consequently, the second step,shown in Fi- 13, step 2, comprises turning switching valve 393 into sucha position that ports H and L remain connected in le ports and O areconnected by a difierent connection separate from that connecting portsH and L. Air news from source 3% through the second manually operableair pressure regulator 311, pipe 312, ports I and O, pipe 333, to thefirst air-operated receiver 314. Any movement of the receiver 314operates the mechanical linkage 313 and the differential 317 so as toadjust flapper 316 relative to nozzle3jl5. Adjustment of flapper 316 andthe consequent variation of pressure at the nozzle 315 operates motor320 andlcau'ses the output air pressure of the pilot valve or relay 319to vary correspondingly. The

from pilot valve 319 is transmitted output pressure 311 causespositioning of final t2 through pipes 323 and 3-24 to Bourdon' tube"-aspire-L325- and causes the second air-pressure-operated indicator toindicate the pressure put out by pilot valve 31?. This indication isgiven by pointer 326 which moves over scale 31% out of the path ofmovement pointer 3499. When the pressure measured by the first indicator309 is equal to that measured by the second indicator 326 these pointerscoincide and'indicate equal pressures by reference to scale 31%. Whenthese two pressures are equal, the switching.

i 316. These corresponding movements of flapper 316 con trol the flow ofair through nozzle 315 and consequently govern the output of air fromrelay 31). The output air from relay 319 is conducted by pipe 323,through ports P and L, and pipe 394 to motor 305. To place the finalcontrol element 306 under the control of measuring element 328, theswitching valve 303 is turned into the posifirm in which it is shown inFig. 13, step 4. In the step 4 position, there is an open communicationbetween ports M and N and a second, separate open connection betweenports P and L. The movements of measuring element 32% in'response to anyvariations of the condition measured by it, moves flapper 332 and thusvaries the air flow through nozzle 331. Consequently, motor 341 operatesrelay 334 so that the output air from relay 3% is trans mi-tted throughpipe 342, ports M and N, and pipe 344 to the second air-operatedreceiver 345. The resulting novernents of receiver 345 move linkage 346,differential 317, and flapper 316. Flapper 316 controls the flow of tionin the pressure in pipe air through nozzle 315 and consequently theoperations of motor 32% which cause corresponding movements of relay319. The output air from relay 319 is conducted through pipe 323, portsP and L, pipe 304 to motor 3%. During thisstep a record of the movementsof measuring element 328 is made on recorder 347 because any varia- 342is transmitted through pipe 349 to the third air-operated receiver 343and causes movements of pen 351 by means of linkage 35%. When it isdesired to operate the final control element 306 automatically inresponse to the variations sensed by measuring element 354 of controller353, switching valve 393 is turned into the position in which it isshown in Fig. 13, step 5. In the step 5 position, there is an opencommunication between ports K and N and a separate and distinct openconnection between ports P and L. Any variations 1 in the condition towhich measuring element 354 is responsive cause corresponding movementsof measuring element 354. Movement of measuring element 354inovesdifferential 356 and flapper 357 relative to nozzle 353. Variations intheair flow through nozzle 353 cause the air-operated motor 359 tooperate pilot valve or relay 360 whose outlet air is conducted throughpipe 364, ports K and N, to the second air-operatedreceiver 345. Anymovements of the second air-operated receiver 345 cause correspondingmovements of the final control element 396 by means of the circuitalready described.

While, in accordance with the provisions of the statutes, I haveillustrated and described the best form of the invention now known tome, it will be apparent to those skilled in the art that changes may bemade in the form of the apparatus disclosed without departing from thespirit of the invention as set forth in the appended claims, and that insome cases certain features of the invention may sometimes be used toadvantage without a corresponding use of other features.

Having now described my invention, what I claim as pew and desire tosecure by Letters Patent is as folows:

1. In an air-operated controller for a motor-operated final'controlelement, a manually operable knob at a control location, a gear traindriven by said knob, 21 flapper valve driven by said gear train, anozzle whose outlet flow is controlled by said flapper valve, a pilotvalve constituting an air-operated transmitter and having an operatingmotor controlled by the outlet flow through said nozzle, a pair ofrelatively movable elements constituting an air-operated repositioningdevice and moving in response to the output flow of said pilot valve, amechanical connection between one of said relatively through said secondnozzle, a measuring element controlling the position of said secondflapper valve, a differential linkage forming the driving connectionbetween said measuring element and said pair of relatively movableelements constituting a second air-operated repositioning device, athird nozzle, a third flapper valve controlling the flow through saidthird a second air-operated transmitter and responsive to the outletflow through said third nozzle,

said measuring element at that instant at the remote location.

2. In an air-operated controller for a motor-operated final controlelement, a manually operable knob at a control location, a gear traindriven by said knob, a flapper valve driven by said gear train, a nozzlewhose outlet flow is controlled by said flapper valve, a pilot valveconstituting an air-operated transmitter and having an operating motorcontrolled by the outlet flow through said nozzle, a pair of relativelymovable elements constituting an air-operated repositioning device andmoving in response to the output flow of said pilot valve, a mechanicalconnection between one of said relatively movable elements and saidflapper'valve for positioning said flapper valve in response to themovements of said relatively movable elements, an air-operatedcontroller mounted at a remote location adjacent the final controlelement and including, a pair of relatively movable elementsconstituting an air-operated receiver and connected so as to be moved inresponse to the output flow of said pilot valve, a second nozzle, asecond pilot valve having an operating motor controlled by the outletflow through said second nozzle, a second flapper valve controlling theflow of air through said second nozzle, a measuring element controllingthe position of said second flapper valve, a differential linkageforming the driving connection between said measuring element and saidsecond flapper valve and having a floating pivot forming a part of saidlinkage, a connection between said receiver and said linkage foradjusting the set point of the controller, a connection between saidsecond pilot valve and the motor for the final control element, a thirdpair of relatively movable elements constituting a second air-operatedrepositioning device, a third nozzle, a third flapper valve controllingthe flow through said third nozzle, a mechanical connection between saidmeasuring element and said third flapper, a third pilot valveconstituting a second air-operated transmitter and having a motorresponsive to the outlet flow through said third nozzle, a connectionbetween the outlet side of said third pilot valve and said third pair ofrelatively movable elements whereby said second repositioning device ismoved in response to the output flow of said third pilot valve, alinkage between said third pair of movable elements and said thirdflapper valve so that said third flapper valve is positioned in responseto movements of said second repositionmg device,

a chart located to receive records from said pen arm and located at thecontrol location adjacent said knob.

3. In an air-operated controller for a motor-operated final controlelement, a manually operable knob at a valve driven by said gear train,

said flapper valve, a pilot valve constituting an air-operatedtransmitter and having an operating motor controlled by the outlet flowthrough said nozzle, a pair of relatively movable elements constitutingan air-operated repositioning device and moving in response to theoutput flow of said pilot valve, a mechanical connection between one ofmovable elements, an air-operated controller mounted at a remotelocation adjacent the final control element and including, a pair ofrelatively movable elements constituting an air-operated receiver andconnected so as to be tial linkage forming the driving connectionbetween said measuring element and said second flapper valve andhavthird pair second revalve and said indicator whereby said indicatorshows the air pressure applied to the motor of the final controlelement.

I control location, having a connection for connecting said first manualregulator to the motor of the final pilot valve and to said lastmentioned connections, a

location adjacent the final control element, a second pair of relativelymovable elements constituting an air-operated repositioning device, asecond nozzle, a second flapper valve controlling the flow of airthrough said secondv nozzle, 2. second: pilot valve constituting anair-operated. transmitter and having am'otor operated inresponseto theflow of air through said second riozzle. a connectionbetween the outputside of said secondpilot valve and'said' repositioning device, alinkagebetweensaid-repositioning device and said second fiapper valve,ia' thirdpair of relatively movable elements constituting a second air-operatedreceiver, a mechanical connection between said second receiver and thedifferential linkage whereby said measuring element moves said firstmentioned flapper valve, a third pair of relativeiy movable elementsconstituting a third air-operated receiver, air conduits formingconnections connecting said second pilot valve to said third receiver, apen arm operated by said second receiver, a chart located at the controllocation adjacent said manually operated airpressure' regulators so asto receive a record from said pen arm, a second measuring element, athird nozzle, a third pilot valve constituting a second transmitter andhaving a motor operable in response to the flow through said thirdnozzle, a third flapper valve controlling the flow through said thirdnozzle, a difierential linkage including a movable pivot and connectingsaid second measuring element to a connection between said secondtransmitter and said second receiver Whereby'said second measuringelement moves said first mentioned fiapper valve and exercises controlover the final control element.

5. In an air operated control system for manually adjusting from acontrol station the set point of a controller, the combinationincluding, a measuring element movable in response to a variable undercontrol, a controller located remote from said control station andadjacent the final control element of the system and operative inresponse to deviations from a given set point by the variable actuatingsaid measuring element, said controller supplying operating compressedair to the motor of the final control element of the system to correctfor said deviations, a control station, an air-operated transmitter atsaid control station, a manually operable knob at said control station,gearing interposed between said knob and said transmitter whereby saidknob operates said transmitter, a receiver connected to said transmitterand operated thereby, adjustable set pointmeans in said con trailer andconnected to said receiver andoperated thereby, whereby the value oi thevariable to be maintained by said controller can transmission systemincluding: a transmittermovable in response to movements. of themeasuring element of said controller and a. second receiver, andair-operated indicating means at said control, station and actuated bysaid second receiver to show the varying: value of the variable measuredby said measuring element, in response to air pressures proportionaltothe values of the variable measured by said measuring element.

6. in an air-operated control system, the combination including, amanually operated transmitter having a manually operable knob, gearingmanually operated by said knob, amovable flapper operated by saidgearing, a nozzle supplied with compressed ai1',ia pilot valve operatedby the varying air pressure in said nozzle, an output pipe connected tosaid pilot valve, a receiver connected to said output pipe, a controllerlocated remote from said conti'ol station and adjacent the final controlelement of the system, said receiver being located in said controller soas to vary the set point of said controller, a measuring element locatedin said controller and movable in response to a variable under control,said controller actuating the motor of the final control element of thesystem, an air-operated transmission system including a secondtransmitter movable in response to the movements of the measuringelement of said controller and including a second receiver, and anindicator located adjacent said knob and connected to said secondreceiver, whereby said indicator shows at the control station the valuesensed llay said measuring element at that instant at the remoteCCEtilOil.

References Cited in the file of this patent UNITED STATES PATENTS beselected at will, an air-operated

